In Great Britain and Ireland the correct spelling of the aristocratic title of this rank is marquess (although for aristocratic titles on the European mainland the French spelling of marquis is often used in English). In Great Britain and Ireland the title ranks below a duke and above an earl (see "Marquesses in the United Kingdom"). A woman with the rank of a marquess, or the wife of a marquess, is a marchioness/ˌmɑːrʃəˈnɛs/[3] in Great Britain and Ireland or a marquise/mɑrˈkiːz/ elsewhere in Europe. The dignity, rank or position of the title is referred to as a marquisate or marquessate.

The theoretical distinction between a marquess and other titles has, since the Middle Ages, faded into obscurity. In times past, the distinction between a count and a marquess was that a marquess's land, called a march, was on the border of the country, while a count's land, called a county, often wasn't. Because of this, a marquess was trusted to defend and fortify against potentially hostile neighbors and was thus more important and ranked higher than a count. The title is ranked below duke, which was often restricted to the royal family and those that were held in high enough esteem to be granted such a title.

In the German lands, a Margrave was a ruler of an immediate Imperial territory (examples include the Margrave of Brandenburg, the Margrave of Baden and the Margrave of Bayreuth), not simply a noble like marquesses/marquises in Western and Southern Europe. German rulers did not confer the title of marquis; holders of marquisates in Central Europe were largely associated with the Italian and Spanish crowns.[citation needed]

The word entered the English language from the Old French marchis ("ruler of a border area") in the late 13th or early 14th century. The French word was derived from marche ("frontier"), itself descended from the Middle Latin marca ("frontier"), from which the modern English words "march" and "mark" also descend. The distinction between governors of frontier territories and interior territories was made as early as the founding of the Roman Empire when some provinces were set aside for administration by the senate and more unpacified or vulnerable provinces were administered by the emperor. The titles "duke" and "count" were similarly distinguished as ranks in the late empire, with dux (literally, "leader") being used for a provincial military governor and the rank of comes (literally "companion," that is, of the Emperor) given to the leader of an active army along the frontier.

In Great Britain and Ireland the correct spelling for an English aristocrat of this rank is marquess. The word "marquess" is unusual in English, ending in "-ess" but referring to a male and not a female. A woman with the rank of a marquess, or the wife of a marquess, is a marchioness in Great Britain and Ireland, or a marquise/mɑrˈkiːz/ elsewhere in Europe. The dignity, rank or position of the title is referred to as a marquisate or marquessate.[a]

"I spoke to Ld M. about the numbers of Peers present at the Coronation, & he said it was quite unprecedented. I observed that there were very few Viscounts, to which he replied "There are very few Viscounts," that they were an old sort of title & not really English; that they came from Vice-Comites; that Dukes & Barons were the only real English titles; — that Marquises were likewise not English, & that people were mere made Marquises, when it was not wished that they should be made Dukes".[5]

The following list may still be incomplete. Feminine forms follow after a slash; many languages have two words, one for the "modern" marquess and one for the original margrave.

In Italy the equivalent modern rank (as opposed to margravio) is that of marchese, the wife of whom is a marchesa, a good example of how several languages adopted a new word derived from marquis for the modern style, thus distinguishing it from the old "military" margraves. Even where neither title was ever used domestically, such duplication to describe foreign titles can exist.

Like other major Western noble titles, marquess or marquis is sometimes used to render certain titles in non-Western languages with their own traditions, even though they are, as a rule, historically unrelated and thus hard to compare. However, they are considered "equivalent" in relative rank.

This is the case with:

In ancient China, 侯 (Hóu) was the second of five noble ranks created by King Wu of Zhou and is generally translated as marquess or marquis. In imperial China, 侯 (Hóu) is generally, but not always, a middle-to-high ranking hereditary nobility title. Its exact rank varies greatly from dynasty to dynasty, and even within a dynasty. It is often created with different sub-ranks.

In Meiji Japan, 侯爵 (Kōshaku), a hereditary peerage (Kazoku) rank, was introduced in 1884, granting a hereditary seat in the upper house of the imperial diet just as a British peerage did (until the House of Lords Act 1999), with the ranks usually rendered as baron, viscount, count, marquis and duke.[6]

In Korea, the title of 현후 (縣侯; Hyeonhu), of which the meaning is "marquess of district", existed for the hereditary nobility in the Goryeo dynasty. It was equivalent to the upper fifth rank of nine bureaucratic orders, and was in the third rank of six nobility orders. In the Joseon dynasty, there was no title equivalent to marquess.

In Vietnam's Annamite realm / empire, hau (侯) was a senior title of hereditary nobility, equivalent to marquis, for male members of the imperial clan, ranking under vuong (king), quoc-cong (grand duke), quan-cong (duke) and cong (prince, but here under duke, rather like a German Fürst), and above ba (count), tu (viscount), nam (baron) and vinh phong (no equivalent).

^Although the vast majority of marquessates are named after places, and hence their holders are known as the "Marquess of X", a very few of them are named after surnames (even if not the bearer's own), and hence their holders are known as the "Marquess X". In either case, he is still informally known as "Lord X", regardless whether there is an of in his title, and it is always safe to style him so.[4]